The seizure comes as tensions mount between the US and Iran over the unravelling nuclear deal between Tehran and world powers, and days after an oil tanker based in the United Arab Emirates disappeared off trackers in Iranian national waters.
The Panamanian-flagged oil tanker MT Riah stopped transmitting its location overnight on Sunday near Qeshm Island, which has a Revolutionary Guard base on it.
Iran’s state TV did not identify the seized vessel, but said it was intercepted on Sunday in south of Iran’s Larak Island in the Strait of Hormuz.
The report added that the oil tanker had 12 foreign crew members on board and was involved in smuggling around one million litres of fuel from Iranian smugglers to foreign customers.
Earlier this week, a US defence official said that America “has suspicions” that Iran seized the oil tanker when it turned off its tracker in the Strait of Hormuz, the Associated Press reported.
An Emirati official said the small oil tanker made no distress call before switching off its tracker.
The 58 metre (190ft) oil tanker typically made trips from Dubai and Sharjah on the UAE’s west coast before going through the strait and heading towards Fujairah on the UAE’s east coast.
Acknowledgement of the recent seizure by Iran’s Revolutionary Guard appears to contradict statements by Iran’s foreign ministry spokesman on Wednesday, who said the country had aided a foreign oil tanker with a malfunction.
The move by the Guard comes after President Donald Trump pulled the US out of Iran’s nuclear deal with world powers last year and imposed sanctions, including on Iranian oil experts, thus heightening tensions between the two countries.
Sky News’ diplomatic editor Dominic Waghorn said the missing MT Riah “went off the radar” a few days ago and was thought to have wandered or towed into Iranian waters.
He added: “The question is, have the Iranian’s seized this smaller tanker that no one is really claiming ownership of, and are they going to parade it as a foreign tanker they’ve seized, and does it have anything to do with the UK?
“The Iranians have been threatening for a while, following the seizure of a supertanker in Gibraltar, that they would settle scores with the UK.”
Iran’s president Hassan Rouhani last week told the UK it faces “consequences” after British forces seized an Iranian oil tanker off Gibraltar.
The Grace 1 was boarded by Royal Marines over accusations it was breaking sanctions by taking an estimated two million barrels of crude oil to Syria.